Fluke 435 user manual 11-6

Fluke 434/435

Users Manual

Tips and Hints

Power mode can be used to record apparent power (kVA) of a transformer over several hours. Look at the Trend and find out if there are times that the transformer is overloaded. You can transfer loads to other transformers, stagger the timing of loads, or if necessary replace the transformer with a larger one.

Interpretation of Power Factor when measured at a device:

•PF = 0 to 1: not all supplied power is consumed, a certain amount of reactive power is present. Current leads (capacitive load) or lags (inductive load).

•PF = 1: all supplied power is consumed by the device. Voltage and current are in phase.

•PF = -1: device generates power. Current and voltage are in phase.

•PF = -1 to 0: device is generating power. Current leads or lags.

If you see negative power or power factor readings and you are connected to a load, check to make sure the arrows on your current clamps are pointing towards the load.

Reactive power (VAR) is most often due to inductive loads such as motors, inductors, and transformers. Installation of correction capacitors can correct for inductive VAR’s. Be sure to check with a qualified engineer before adding PF-correction capacitors, especially if you measure current harmonics in your system.

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